Flexible rotor



p 1951 F. RICKERICH, JR., ETAL 2,567,448

FLEXIBLE ROTOR Filed June 22, 1946 INVENTORS FPEDtW/(A R/(KEf/(H, JR BY NELSO/V J. EDG

Patented Sept. 11,1951

FLEXIBLE ROTOR.

Frederick Rickerich,Jr., Morsemere, and Nelson J. Edge, JerseyCity, N. J.,-assignors to Colloid Corporation of America, Jersey Gity,-N. J., a corporationo fDelaware Application June-22; 1946; 1Serial No; 6378;642;

6 Claims-.- (01. 241-3496);

Thepresent invention relates to rotors for rotary: grinding mills and refers more particularly to-improvements in the flexible rotor disclosed in UuSJLetters Patent 1,995,549 to Myers.

Thestructure of the Myers rotor comprises a hub portion, an intermediateflexible web and a rim portion having a grinding' face and a center ofgravity displaced laterally on the opposite: side of-zthe:.-web from. the grinding face. In. certain applications it was desired to constructthe grindingface of. very hard materials and to fasten it to the: flexible supporting web,. along with a heavier' flywheel portion disposed on the opposite sidexofthe. web.. One such structure exhibited nddeflectionof the grinding face toward a coopcratinggrinding element at speeds as 'high as IOIlOOJR'. Pl M2, and it was presumed that the rigidity of the rimwas preventing the desired flexing action of the assembly.

An object of the present invention is the provision-ofa composite flexible rotor which will. be responsive to. laterally deflective forces generated byrapid: revolution ofthe laterally offset mass of therim.

, A further object is to'increase the ability of any flexible. rotor according to the former disclosure to flex in response to revolution.

Other. objects. will .become apparent in the course. of the within I specification.

In accomplishing. the objects of the present invention it was-found desirable todivide the flywlheelor a portion thereof along. peripherally displaced lines, creating a plurality. of distinct at leastpartially distinct, circumferentially separated elements firmly connected to and constituting a part of the rim, and thereby decreasing. the rigidity of the rim. It was further foundthat if .the lines of division were inclined to theradii ofthe. rotor, the walls of the cuts would act as airscoops and have a cooling effect on therim, which according to the attrition principleof operation generates considerable heat.

In operation the rotor with divided or slotted flywheel -is preceptibly more flexible, and also runs cooler.

The: invention will appear more clearly from the; following detailed description when taken in connection .with the accompanying drawings, showing, by way of example, preferredembodiments-zof the inventive idea.

: Imthe drawings, Figure 1 is a vertical section OfQaB rotor embodying the invention, taken along the:line.-.;l-'-| of Figure 2..

Figure-2 is a bottom elevation ofzthe same;

. 2" Figures-3 and 4 are-fragmentary side-and bot tom elevations' respectively of another form of the invention.

Figures 5 and 6 are-fragmentary bottom and side elevations respectively of the preferred form of the invention.

Figure is a hypothetical side elevation of" the preferred form of the invention at a given-moment during rapid revolution, certain lines: being omitted for the sake of clarity.

Referring to Figures 1 and 2', the rotor hubcomprises a collar-plate l1 and flanged cylinder l9 mounted on the vertical mill shaft by a nut Mand bolted or otherwise joined to eachother so as to hold between them the flexible diaphragm l za The grinding ring I'lis mounted on the front side of' diaphragm-l2- and the heavy flywheel I6 is mounted on' the-rear side thereof, bolts passing through'all three.- The ring H and flywheel-Hi constitute a rim portion the center of gravity of which is disposed on the opposite side of the diaphragmfrom-the grinding surface, and on rapid revolution the rim-ls adapted to be deflected laterally towards an opposed grinding surface: The-composite construction of the rim-was resorted toin order to permit a choice of materials for, and forgingand heattreating of the grinding ring=,= while in :any: event the diaphragmis' of spring steel -,andthe flywheel is of mild steel or other plentiful substance. The above construction isnot a literal embodiment of the Myers disclosure and did not exhibit the desired flexing action at speeds as high as 10,800 R. P. M. of a severrinch diameter rotor. Theoretical consideration of the problem thus presented sugg sted that a tendency toward the desired effect might be present but be effectually resisted by the-rigidity offthe ring-and of the flywheel,- particularly the latter.

\ Thesimplestform ofthe indicated solution consists in forming in the flywheel a plurality of substantially radial slitsor cuts l 8' of uniform depth throughout their length and extending forwardfrom the rear surface of the flywheel-I6 substantially from the inner to the outer diameterthereof at-said-rear surface, resulting in a 'plural-ityof circumferentially separated segments I7 each integral-with and located rearwardly of the greatly =reduced continuous annular portion lE-Which is of uniform axial thickness dueto the unifbrmndepth'of s10tsl-8.- In such form the flywheer I6 may: be considered to be no more-rigid than the annular portion l5 thereof; As clearly illustrated, the-segments ll greatly exceed in axial thickness the annular portion 15.

Another form of the improvement constituting the present invention is illustrated in Figures 3 and 4. This form has no flywheel in the ordinary sense, the flywheel means being the flywheel assembly 26 consisting of a multiplicity of distinct segments 21 through bolted to the grinding ring 2| and diaphragm 22 or otherwise joined to the diaphragm opposite the grinding ring in aggregately circular arrangement, the spaces 28 being intermediate the segments 21, viewed in plan and with the eye progressing circumferentially. .This modification has the advantage of maximum flexibility, and the additional advantage of creating air currents which tend to cool it. It is however expensive to build and particularly to balance.

The preferred form of the invention, illustrated in Figures 5, 6 and '1, is flexible, air cooled and easy to fabricate. The grinding ring 3|, diaphragm 32 and flywheel 36 are bolted or otherwise joined together in concentric, parallel relation.- A multiplicity of slots 38, 48 are formed in the flywheel 36, leaving a continuous annular portion 35 adjacent the diaphragm 32. The slots 38 are angularly inclined to the radii of the flywheel, and the slots 48 are equally and oppositely inclined and form angles with the slots 38 substantially at theouter periphery of the flywheel. Included in these angles are the substantially triangular portions 41 with their apexes directed outwardly, and between successive angles are the larger substantially triangular portions 31 with their apexes directed inwardly. The portions 31, 41 may be said to be circumferentially separated even though the slots 38, 48 separating them do not extend radially. The center of mass of each portion 31, 41 is'spaced circumferentially from that of its neighbor, and the eye of an observe:- travelling circumferentially views first one, then another. It should be stated however that separateness of the portions 31, 41 does not imply that there must be any certain amount of space between them, since our research indicates that the discontinuous relation of the separate elements one to the other rather than the fortuitous existence of spaces between them is the reason for the success of the present invention.

The flexibility of this form of the invention results in a lateral deflection of the grinding ring equal to one thousandth of an inch for each 1800 R. P. M. of a seven inch diameter rotor, such deflections having been observed at 1800 R. P. M. and at each multiple thereof up to 10,800 R. P. M. The observed rotor was, except for the modification herein described, identical with the one which had exhibited no deflection at the latter speed.

An elevated of the rotor in the form which it is presumed to have during rapid revolution is shown in Figure 7, wherein the deflected relation of parts is shown greatly exaggerated. The outside diameter of the grinding surface of the ring 3| ha been designated 4|, and the inside diameter thereof has been designated 5|. The outside .diameter of the bottom surface of the flywheel 36 has been designated 46 and the inside diameter thereof has been designated 66, while the inner peripheral surface of the flywheel is designated 56 and the outer peripheral surface thereof is designated 16. The line 42 is at the .height of the upper surface of diaphragm 32 at the outside diameter of the rotor, and the line 52 at the height thereof at the hub. The shaft being fixed against axial movement has a constant height.

Figure '7 may be compared to Figure 1, whose silhouette is identical except that the parts are in undeflected relation. In Figure 1 the nut |4 appears projecting substantially above the surface of ring I I, while the lower surface of flywheel I6 is below the flange of cylinder I9. In Figure '1 the flywheel 36 is seen tipping outward and upward, the inner and outer peripheral surfaces 58 and 16 thereof being inclined outward from the diaphragm 32 which supports the flywheel. The walls of the individual slots 36, 48 are each inclined from the vertical substantially parallel to the peripheral surfaces 56, 16 ninety degrees removed from them circumferentially. A corresponding inclination of the walls of slots l8 and spaces 28 may be predicated. The above hypothesis of the desired inclination of the peripheral surfaces 56, 16 indicated the necessity of separate flywheel components capable of inclination one to the other as shown by the walls of slots 38, 48 of- Figure '7, in order to permit the inclination of surfaces 56, 16. The flywheel 36 being thus deformed, produces the lateral deflection 42-52 of the outer periphery of diaphragm 32 and ring 3|, the operative surface of ring 3| thereupon assuming the saucer like shape shown in Figure '1 and originally described by Myers.

Referring to Figure 6, it is evident that revolution of the rotor clockwise will constitute the slots 38 air scoops adapted to capture and conduct circumambient air from outside the flywheel 36 to the space interior thereof, while the slots 46 are constituted scoops which capture and conduct air from the inner peripheral surface 56 to the outer surface 16. counterclockwise revolution has the same effect, with an exchange of function taking place between the slots 38 and 48, that is, slots 4-8 bring outside air in, and slots 38 exhaust the inside air. In all of the embodiments above described, the elements I1, 21, 31, 41 have substantial thickness in the direction of the axes of their respective rotors, thus substantially distinguishing the very shallow corrugations 3| and raised portions 34 ofMyers 1,995,549 which have no apparent connection with the alleged flexibility of that construction.

It is apparent that the specific illustrations shown above have been given by way of illustration only and not by way of limitation, and that the structures above described are subject to wide variation and modification without departing from the scope of the invention, all of which variations and modifications are to be included within the scope of the present invention.

What is claimed is:

- 1. In a rotary grinding apparatus of the type comprising a hub, a rim and a flexible web connecting said hub and said rim, the center of gravity of said rim being located on the opposite side of said web from the grinding face of said rim, the improvement consisting in said rim being divided by cuts extending forwardly from the rear surface thereof, said cuts further extending substantially from the inner to the outer circumference of said rim at said rear surface, said cuts being inclined to radii of said rim, and alternate cuts being oppositely inclined. v

2. A flexible rotor for rotary grinding apparatus, comprising in combination a hub portion, a

rim portion and a flexible diaphragm supporting said rim portion in operative relationship to said hub portion, said rim portion comprising a radial annular grinding element, said rim portion further comprising a flywheel portion located rearwardly of said grinding element, the center of gravity of said rim portion, being located rearwardly of said diaphragm, said rim portion comprising a plurality of circumferentially separated elements, said elements being of substantial thickness in the direction of the axis of said rotor, the separateness of said elements one from the other in a circumferential sense permitting distortion of said rim portion and consequent forward actuation of said grinding element axially toward an opposed work surface when said rotor is rapidly rotated.

3. A flexible rotor for rotary grinding apparatus comprising in combination a hub portion, a ri portion and a flexible diaphragm supporting said rim portion in operative relationship to said hub portion, said rim portion comprising a radial annular grinding element, said rim portion further comprising a flywheel portion located rearwardly of said grinding element, the oenterof gravity of said ri-m portion being located rearwardly of said diaphragm, said flywheel portion comprising a continuous annular portion and a plurality of circumferentially separated portions extending rearwardly from said annular portion and integral therewith, said last mentioned portions being of substantial thickness in the direction of the axis of said rotor, the separateness of said portions one from the other in a circumferential sense permitting distortion of said flywheel portion and consequent forward actuation of said grinding element axially toward an opposed work surface when said rotor is rapidly rotated.

4. In a flexible rotor according to claim 3, said circumferentially separated portions further exceeding said annular portion in dimension in the direction of the axis of said rotor.

5. A flexible rotor for rotary grinding apparatus, said rotor comprising a hub portion, a rim portion and a flexible diaphragm connecting said hub and said rim portions, the center of gravity of said rim portion being located rearwardly of said diaphragm, said rim portion comprising radial annular grinding means located forwardly of said diaphragm portion, said rim portion further comprising flywheel means located rearwardly of said grinding means, said flywheel means comprising a plurality of distinct elements firmly connected to said grinding means, said elements being circumferentially spaced one from the other, the separateness of said elements one from the other in a circumferential sense permitting distortion of said flywheel means and consequent forward actuation of said grinding means axially toward an opposed work surface when said rotor is rapidly rotated.

6. In a flexible rotor for rotary grinding apparatus, a hub portion, a rim portion, and a flexible metallic diaphragm connecting said hub and rim portions, said rim portion comprising a radial annular grinding element, said rim portion further comprising an annular flywheel portion located rearwardly of said grinding element, the center of gravity of said rim portion being located rearwardly of said diaphragm, said flywheel portion comprising a plurality of elements of substantial dimension in the direction of the axis of said rotor, said elements being separated one from the other in a sense circumferential of said rotor, the separateness of said portions one from the other in a circumferential sense permitting distortion of said flywheel portion and consequent forward actuation of said grinding element axially toward an opposed work surface when said rotor is rapidly rotated.

FREDERICK RICKERICH, JR. NELSON J. EDGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 122,129 Myers Dec. 26, 1871 267,999 Cadwgan Nov. 28, 1882 1,731,784 Madsen Oct. 15, 1929 1,995,549 Myers Mar. 26, 1935 2,097,890 Myers Nov. 2, 1937 2,108,502 Muerch Feb. 15, 1938 

